There are four cells per 12V/10Ah block.
Bob, is the BMS connected to each cell junction? Where do the smaller wires go to? It would need access to each cell to do LVC at the cell level. I'm not sure how they would do balancing, as it would need to dissapate more heat if it worked the way most RC balancers work If there were some sort of clamping system, to limit the voltage a cell sees, thee's have to be more FETS, right? I'm guessing that it does individual cell monitoring, for the LVC function, and maybe temp monitoring, but not cell balancing, per se. There is the upper 4.0V limit for over-charging, so maybe that's all that is needed?
It is disappointing that the BMS is limiting these to 5C, or 50A. The cells are suposed to be good for 10C continuous. What sets these cells and the a123s apart from the typical Chinese LiFe offerings is their ability to provide much higher current levels. The Eonyx pack
needs to be 20Ah, just to be able to handle a 40-50A load. I think 90% of users don't need more than 10Ah of capacity, 90% of the time. The 50A fuse in these is a last line of defense, it seems, so I'm guessing the RISC controller-based current limiter is set for something lower than that. If it is 40A, that will still work with many setups, but probably not some of the ones people are using here, with modified controllers.
As for the weight issue, at 9 pounds for 12, that means each cell weighs 3/4 pounds, or 340 gm. That's about 34 gm per Ah. A single 2.3Ah a123-M1 cell weghs 72 gm, or about 31 gm per Ah, which is pretty close. Clearly, all the "extra" weight is in the nuclear blast survivable cases.
I definitely think we need some "ebike-friendlier" packaging for these. In most of the setups that would be candidates for these, I would think 48V, not 36V would be a more common configuration, which would mean 25 pounds for a 10Ah pack. It should really be about half of that.
-- Gary
. I am pretty sure that my 36v10a LiMn from FalconEV weighs 10.2 lbs, and is packaged in a solid metal case. I think the 15ah LiMn was 12.5lbs, so on them the case counts for a good bit.
